In 6D, surely the bar should be before the first entered letter, i.e., after the missing letter. There should be a hyphen in 23D, but, again, before the first entered letter.
I feel any hyphens or underlines should precede the entered answers in every case (and therefore not show at all).
Or have I got it wrong?
Either way, I'm not too worried, as it all fits in so far (as long as 6D does begin with an F).